The overall goal of this program is an elucidation of the basic intermediatry metabolic pathways of gastropod vectors of animal parasites and an understanding of how this metabolism may be modified to support their various modes of life. Immediate objectives for this period are: (1) An evaluation of the physiological function of mannitol oxidases, an enzyme recently discovered in our laboratory. Mannitol oxidase catalyzes the conversion of mannitol to mannose and is neither pyridine nucleotide-dependent nor cyanide-sensitive. Specific investigations to be made include a determination of the metabolic transformation of mannose, especially conversions to glycoproteins and glycolipids, the purification and characterization of mannitol oxidase, a determination of its subcellular localization, and an examination of certain aspects of its regulation such as induction by dietary mannitol, its isozymic forms and alterations of its activity during schistosome infection or transition to the estivating state. (2) An understanding of the mechanism by which these animals generate high energy phosphate during different physiological states. Specific areas to be investigated include first, an assessment of mitochondrial function with regard to the oxidative phosphorylating potential of herbivorous hepatopancreas mitochondria and the nature of the respiratory chain components and secondly, a determination of the major pathways of carbohydrate metabolism (glycolytic pathway, tricarboxylic acid cycle) and their regulation. Contemporary biochemical methodology and instrumentation will be utilized for these investigations.